Valmiki Ramayana Sundara Kanda Sarga 58 Shloka 52
Original Shlokaतत स्सीतामपश्यंस्तु रावणस्य निवेशने। शोकसागरमासाद्य न पारमुपलक्षये।।5.58.52।।
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रावणस्य Ravana's, निवेशने residence, सीताम् Sita, अपश्यंस्तु not able to find, ततः then, शोकसागरम् ocean of sorrow, आसाद्य immersed, पारम् endless, न उपलक्षये did not know.
"Not able to find Sita at the residence of Ravana I was immersed in an ocean of endless sorrow and did not know what to do.